(Magnet is very strong. Stronger than magnetic feet that I have previously owned and flown not from the roof are tested up to 120 km / h)
The range has impressed us and is much higher than the one of another manufacturer 70cm antenna.
A good friend whispered to me that she had to run very well with about 50W. The foot (coil) was not warm. There is so much room for improvement.
The bottom of the magnet is covered only by a very thin film. There may be caused by irregularities in the magnet or dirt between the magnet and slide "Huckel". The extent to which this has to be proved empirically enforce the roof of a car.
(Estimate for the range: cultivated urban area with contour lines (ie worst-case scenario) were about 10km there as long as the other party has a roof antenna)